The present invention relates to an engine oil passage seal of the type comprising a hollow dowel connecting oil passages in two casing parts and a sealing ring compressed around the dowel between the two casing parts.
Such seals are in common use in automobile and other engines. The hollow dowels serve both to locate the casing parts and to complete oil passages between the casing parts while the sealing rings prevent oil leaking out between the casing parts. The known seals use ordinary O-rings. Although these are cheap, they do not provide a satisfactory seal unless they are correctly and uniformly compressed. For this reason, it is necessary to maintain very close tolerances on the relative positions of the dowel holes in the casing parts (and on any gap between the casing parts when fitted together) and to use close fitting dowels. Since there are normally several dowels between two casing parts, this makes it difficult to fit the parts together and to separate the parts. There is a risk, if parts are not offered up and taken off squarely, that the dowels and/or O-rings will be damaged, leading to oil leaks.